Abstract: Rydberg atoms are highly excited atoms with a large principal quantum number n. Rydberg atoms are very sensitive to external electric fields due to their large polarizability. As the atomic energy level shift is directly related to the electric field, Rydberg atoms can be used to accurately measure the strength and frequency of external electric field. In this paper, the preparation of 20S_1/2 Rydberg state of cesium atoms at room temperature is realized by two-photon excitation, and the measurement of electric field at industrial frequency is realized based on electromagnetically induced transparency (EIT) spectroscopy of Rydberg atoms. In the experiment, the relationship between the amplitude and frequency of the power frequency electric field and the frequency shift of the EIT is studied, and the measurements of the strength and frequency of the power frequency electric field are realized. Meanwhile, the frequency shift of the EIT spectrum is the key to measuring the characteristics of the electric field. We adopt the electro-optic modulator to modulate the phase of the probe light. The frequency interval between the side band peak generated on both sides of the EIT spectrum and the main peak is strictly equal to the frequency of the radio frequency source of the electro-optic modulator. This frequency acts as a calibration criteria to enable accurate measurement of the EIT spectral frequency shift. We design a micro all-fiber structure sensor, which can realize the remote measurement of electric field. The research scheme in this paper has important reference value for the traceable and accurate measurement and engineering application of outdoor high-voltage power frequency electric field, and it is suitable for the measurement requirements of new power system construction.